Abstract: Hollow polymer microspheres about 5 m in diameter were synthesized by dynamic swelling method using micron-sized polystyrene spheres with positive charges on surfaces as seeds. The synthesis process included swelling by organic solvents such as toluene and divinylbenzene, polymerizing and coating. The influences of variety and dosage of organic solvents on diameter, size distribution and hole structure of hollow microspheres were investigated, and the formation mechanism of hollow microspheres was discussed. It is indicated that some volatile organic solvents, such as toluene and dimethylbenzene, are crucial to hollow structure formation. Experimental results show that, more toluene leads to larger hollow structure after swelling, and dimethylbenzene is good for hollow structure formation, owing to its low solubility.